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May a "landlubber" comment? - was[ Help create better charts]
The line of sight estimator for distance versus height above sea level goes something like this: distance n.m. = 1.2 sqrt (Height ft MSL) That calculation follows directly from the Taylor series for Cosine: 1 - x^2/2! + x^4/4! - ... It means that for very small angles, the height above the sea is 1 - (1 - x^2/2!) = x^2/2! = x^2/2 (when R == 1) Insert the radius of the Earth (in nautical miles, 3500 or so) and multiply the result by the number of feet in a nautical mile (about 6000+) and the 1.2 factor should pop out. Terje For a more exact result you only need to use Pythagoras. Jeff |
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